1. Field of the Invention
The present invention relates to a cutting tool and a cutting machine, used in attached to a machine tool and the like, for cutting a working point on a work with cutting fluid being supplied there. More particularly, it relates to a cutting tool and a cutting machine used for fine processing on high precision mold core for optical surface.
2. Description of the Related Art
Since past, cutting operations by cutting tools have been carried out by supplying cutting fluid to a tip portion of the tools. This is to cool down a tool and a work and to remove chips there from. What is important for cutting operation is that cutting fluid shall constantly reach the working point. This is required especially when working on high precision mold core for optical surface and the like wherein fine structure of μm-order is to be formed by cutting. That is, if cutting fluid does not reach a working point when fine processing is done, shortage of the cutting fluid can possibly cause abrasion and breakage of the tool. If the abraded or broken tool keeps on cutting operation, machining accuracy deteriorates.
There have conventionally been devised the following methods for supplying cutting fluid to a tip portion of a tool. A first method is to spray cutting fluid from a nozzle arranged near to the cutting tool. Another method is to provide a fluid passage inside of a cutting tool to spout cutting fluid from an opening arranged near to the working point. For example, Japanese Unexamined Patent Publication No. 10-296506 discloses a cutting tool of which a nozzle is removably attached near to the cutting tool. Japanese Unexamined Patent Publication No. 8-25111 discloses a turning tool with a cutting fluid passage being formed inside.
However, the above-mentioned conventional tools have had the following problems. Relating to the conventional method to arrange a cutting fluid nozzle near to a tool, as disclosed in the Publication No. 10-296506, degree of closeness of the nozzle to the tool is limited. Furthermore, the tool and a working object meet each other very closely at a working point. Therefore, cutting fluid is hard to go into a narrow space between the tool and the working object. Consequently, there arises a problematic case that cutting fluid is not constantly supplied to the working point appropriately. Especially for the case of cutting operation of micro-level structure, a cutting tool itself is small. On that account, shortage of cutting fluid even for an instant can possibly cause damage to the tool. So, more reliable fluid supplying method has been demanded.
Furthermore, relating to another conventional method to provide a cutting fluid passage inside of the tool, as disclosed in the Publication No. 8-25111, it is difficult to design and form the passage and a supply route of cutting fluid. Especially for the case of fly-cut method and the like wherein a cutting tool is moved, special structure for cutting fluid supply is required, which is problematic.